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Novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime

A Beckmann rearrangement, cyclohexanone oxime technology, applied in the preparation of lactams, chemical instruments and methods, chemical/physics/physicochemical processes, etc., can solve the problem of poor safety and reliability of reactors and reaction processes, Baker The calorific value of the MAN rearrangement reaction is large, and the temperature is difficult to control, so as to improve the controllability and safety, reduce the amount of material stagnation, and reduce the output.

Active Publication Date: 2010-11-24
TSINGHUA UNIV
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  • Summary
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

The Beckmann rearrangement reaction generates a lot of heat and the temperature is not easy to control. Conventional reactors use external circulation to obtain heat, and the circulation ratio can be as high as 245, which leads to low equipment production capacity, high operating costs, and safety and security of the reactor and reaction process. poor reliability

Method used

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  • Novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime
  • Novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime
  • Novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime

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Effect test

Embodiment 1

[0023] A new Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime, specifically as follows:

[0024] (1) using a microreactor, using SO 3 Content is the oleum of 20wt.% as dispersed phase, and adopting mass fraction is the cyclohexanone oxime n-octane solution of 10% as continuous phase, and the flow rate of dispersed phase is 0.8mL / min, and the flow rate of continuous phase is 25mL / min, two The latter are rapidly mixed in the microreactor and trigger the Beckmann rearrangement reaction, the acid oxime ratio of the reaction is 1.06, and the reaction system temperature is 70 °C;

[0025] (2) the residence time of the mixed reaction mass in the delay pipeline connected with the outlet of the microreactor is 40s, and ripening is carried out to complete the reaction;

[0026] (3) The matured product is passed into another microreactor as a continuous phase, mixed with the water passed in as a dispersed phase, and a hydrolysis reaction occurs, the hydro...

Embodiment 2

[0034] According to the same method as in Example 1, the temperature of the reaction system was raised from 70° C. to 80° C., and other conditions were the same as in Example 1. The product was analyzed, and the conversion rate of the reaction reached 100%, and the selectivity reached 99.9%.

Embodiment 3

[0036] According to the same method as in Example 1, in step (1), the flow rate of the dispersed phase was increased from 0.8 mL / min to 0.9 mL / min, and the acid oxime ratio was 1.19 at this time. The temperature of the reaction system was increased from 70°C to 80°C, and other conditions were the same as in Example 1. The product was analyzed, and the conversion rate of the reaction reached 100%, and the selectivity reached 99.9%.

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Abstract

The invention discloses a novel Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime, and belongs to the technical field of chemical reaction engineering. The method comprises the following steps of: by using high-efficiency mixing and excellent mass transfer and heat transfer properties of a microreactor, using fuming sulphuric acid as a dispersed phase in a first microreactor, dissolving the cyclohexanone oxime in an inert solvent to serve as a continuous phase, mixing the two phases and initiating an rearrangement reaction; taking the cured reaction mixture as a continuous phase, introducing the continuous phase into a second microreactor, mixing with the introduced water serving as the dispersed phase, performing hydrolysis reaction to obtain caprolactam-containing aqueous solution, and circulating the inert solvent back to the system. The method only needs the reaction time of 10 to 40 seconds in a large acid oxime ratio of 0.8 to 3.0, namely can achieve high conversion rate of over 99.9 percent and high selectivity of over 99.9 percent, and has the advantages of high operational flexibility, low operating cost, high safety and controllability, high production efficiency, and capacity of greatly reducing the yield of a byproduct ammonium sulfate.

Description

technical field [0001] The invention belongs to the technical field of chemical reaction engineering, in particular to a new Beckmann rearrangement method for preparing caprolactam from cyclohexanone oxime. Background technique [0002] ε-caprolactam is an important organic chemical raw material, mainly used in the production of nylon 6 fiber (nylon 6) and nylon 6 engineering plastics. Among them: nylon 6 fiber is widely used in wool spinning, knitting, weaving, carpet and other industries, and nylon 6 engineering plastics is widely used in electronics, automobiles, packaging films and other industries. By the end of 2007, my country's import of caprolactam reached 468,000 tons, and the import dependence reached 60.9%. [0003] The conversion of cyclohexanone oxime to caprolactam through liquid-phase Beckmann rearrangement reaction is a technology commonly used in industry at present, and the catalyst used is usually concentrated sulfuric acid or oleum. The caprolactam pro...

Claims

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Application Information

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IPC IPC(8): C07D223/10C07D201/04B01J19/00
Inventor 骆广生张吉松王凯吕阳成
Owner TSINGHUA UNIV
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